Medium
F.12 on Vaillant ecoTEC plus Regular

Your boiler has lost the ability to read the temperature of your hot water tank because a sensor has developed an electrical fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Shortcircuit:Cylindertemperaturesensor

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

F.11View →F.13View →

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